FKIE_CVE-2026-68367
Vulnerability from fkie_nvd - Published: 2026-08-10 13:20 - Updated: 2026-08-17 06:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
usb: gadget: f_tcm: synchronize delayed set_alt with teardown
The f_tcm set_alt() path defers endpoint setup to a work item and
completes the delayed status response from process context. The delayed
work uses f_tcm private state and may complete the setup request after
disconnect or function teardown has already moved on.
Cancel and drain the delayed set_alt work when the function is unbound or
freed. For disable paths, which are reached under the composite device
lock, use a small state machine and a non-sleeping cancellation path
instead of cancel_work_sync(). If the work is already running, mark it
cancelled and let the worker own the cleanup; otherwise tcm_disable() can
cancel the queued work and clean up immediately.
Also serialize the final delayed-status completion with the cancellation
check while holding the composite device lock. This prevents a disconnect
from clearing delayed_status while the worker is about to complete the
control request.
Validation reproduced this kernel report:
BUG: KASAN: slab-use-after-free in tcm_delayed_set_alt+0x6c/0xef0
Call Trace:
<TASK>
dump_stack_lvl+0x66/0xa0
print_report+0xce/0x630
? tcm_delayed_set_alt+0x6c/0xef0
? srso_alias_return_thunk+0x5/0xfbef5
? __virt_addr_valid+0x188/0x320
? tcm_delayed_set_alt+0x6c/0xef0
kasan_report+0xe0/0x110
? tcm_delayed_set_alt+0x6c/0xef0
tcm_delayed_set_alt+0x6c/0xef0
? __pfx_tcm_delayed_set_alt+0x10/0x10
? process_one_work+0x4cb/0xb90
? rcu_is_watching+0x20/0x50
? tcm_delayed_set_alt+0x9/0xef0
process_one_work+0x4d7/0xb90
? __pfx_process_one_work+0x10/0x10
? srso_alias_return_thunk+0x5/0xfbef5
? __list_add_valid_or_report+0x37/0xf0
? __pfx_tcm_delayed_set_alt+0x10/0x10
? srso_alias_return_thunk+0x5/0xfbef5
worker_thread+0x2d8/0x570
? __pfx_worker_thread+0x10/0x10
kthread+0x1ad/0x1f0
? __pfx_kthread+0x10/0x10
ret_from_fork+0x3c9/0x540
? __pfx_ret_from_fork+0x10/0x10
? srso_alias_return_thunk+0x5/0xfbef5
? __switch_to+0x2e9/0x730
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1a/0x30
</TASK>
Allocated by task 544:
kasan_save_stack+0x33/0x60
kasan_save_track+0x14/0x30
__kasan_kmalloc+0x8f/0xa0
tcm_alloc+0x68/0x180
usb_get_function+0x36/0x60
config_usb_cfg_link+0x125/0x1b0
configfs_symlink+0x322/0x890
vfs_symlink+0xc2/0x270
filename_symlinkat+0x295/0x2f0
__x64_sys_symlinkat+0x62/0x90
do_syscall_64+0x115/0x6a0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 661:
kasan_save_stack+0x33/0x60
kasan_save_track+0x14/0x30
kasan_save_free_info+0x3b/0x60
__kasan_slab_free+0x43/0x70
kfree+0x2f9/0x530
config_usb_cfg_unlink+0x173/0x1e0
configfs_unlink+0x1fa/0x340
vfs_unlink+0x15c/0x510
filename_unlinkat+0x2ba/0x450
__x64_sys_unlinkat+0x63/0x90
do_syscall_64+0x115/0x6a0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/usb/gadget/function/f_tcm.c",
"drivers/usb/gadget/function/tcm.h"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "3118bb872c7dff653294f193d5328a476619e04d",
"status": "affected",
"version": "c52661d60f636d17e26ad834457db333bd1df494",
"versionType": "git"
},
{
"lessThan": "a6eb5a0ae7cd313cfd7df78decd8f43b64c68703",
"status": "affected",
"version": "c52661d60f636d17e26ad834457db333bd1df494",
"versionType": "git"
},
{
"lessThan": "f282242906c12fd476b86757afba51f211d4f959",
"status": "affected",
"version": "c52661d60f636d17e26ad834457db333bd1df494",
"versionType": "git"
},
{
"lessThan": "4c6c6a5588b9a2f8437fb794e852d05fa60ebe53",
"status": "affected",
"version": "c52661d60f636d17e26ad834457db333bd1df494",
"versionType": "git"
},
{
"lessThan": "79e2d75725c85607f8a9d87ae9cace62a19f767d",
"status": "affected",
"version": "c52661d60f636d17e26ad834457db333bd1df494",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"drivers/usb/gadget/function/f_tcm.c",
"drivers/usb/gadget/function/tcm.h"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "3.5"
},
{
"lessThan": "3.5",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.151",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.103",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.42",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.6",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_tcm: synchronize delayed set_alt with teardown\n\nThe f_tcm set_alt() path defers endpoint setup to a work item and\ncompletes the delayed status response from process context. The delayed\nwork uses f_tcm private state and may complete the setup request after\ndisconnect or function teardown has already moved on.\n\nCancel and drain the delayed set_alt work when the function is unbound or\nfreed. For disable paths, which are reached under the composite device\nlock, use a small state machine and a non-sleeping cancellation path\ninstead of cancel_work_sync(). If the work is already running, mark it\ncancelled and let the worker own the cleanup; otherwise tcm_disable() can\ncancel the queued work and clean up immediately.\n\nAlso serialize the final delayed-status completion with the cancellation\ncheck while holding the composite device lock. This prevents a disconnect\nfrom clearing delayed_status while the worker is about to complete the\ncontrol request.\n\nValidation reproduced this kernel report:\nBUG: KASAN: slab-use-after-free in tcm_delayed_set_alt+0x6c/0xef0\n\nCall Trace:\n \u003cTASK\u003e\n dump_stack_lvl+0x66/0xa0\n print_report+0xce/0x630\n ? tcm_delayed_set_alt+0x6c/0xef0\n ? srso_alias_return_thunk+0x5/0xfbef5\n ? __virt_addr_valid+0x188/0x320\n ? tcm_delayed_set_alt+0x6c/0xef0\n kasan_report+0xe0/0x110\n ? tcm_delayed_set_alt+0x6c/0xef0\n tcm_delayed_set_alt+0x6c/0xef0\n ? __pfx_tcm_delayed_set_alt+0x10/0x10\n ? process_one_work+0x4cb/0xb90\n ? rcu_is_watching+0x20/0x50\n ? tcm_delayed_set_alt+0x9/0xef0\n process_one_work+0x4d7/0xb90\n ? __pfx_process_one_work+0x10/0x10\n ? srso_alias_return_thunk+0x5/0xfbef5\n ? __list_add_valid_or_report+0x37/0xf0\n ? __pfx_tcm_delayed_set_alt+0x10/0x10\n ? srso_alias_return_thunk+0x5/0xfbef5\n worker_thread+0x2d8/0x570\n ? __pfx_worker_thread+0x10/0x10\n kthread+0x1ad/0x1f0\n ? __pfx_kthread+0x10/0x10\n ret_from_fork+0x3c9/0x540\n ? __pfx_ret_from_fork+0x10/0x10\n ? srso_alias_return_thunk+0x5/0xfbef5\n ? __switch_to+0x2e9/0x730\n ? __pfx_kthread+0x10/0x10\n ret_from_fork_asm+0x1a/0x30\n \u003c/TASK\u003e\n\nAllocated by task 544:\n kasan_save_stack+0x33/0x60\n kasan_save_track+0x14/0x30\n __kasan_kmalloc+0x8f/0xa0\n tcm_alloc+0x68/0x180\n usb_get_function+0x36/0x60\n config_usb_cfg_link+0x125/0x1b0\n configfs_symlink+0x322/0x890\n vfs_symlink+0xc2/0x270\n filename_symlinkat+0x295/0x2f0\n __x64_sys_symlinkat+0x62/0x90\n do_syscall_64+0x115/0x6a0\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nFreed by task 661:\n kasan_save_stack+0x33/0x60\n kasan_save_track+0x14/0x30\n kasan_save_free_info+0x3b/0x60\n __kasan_slab_free+0x43/0x70\n kfree+0x2f9/0x530\n config_usb_cfg_unlink+0x173/0x1e0\n configfs_unlink+0x1fa/0x340\n vfs_unlink+0x15c/0x510\n filename_unlinkat+0x2ba/0x450\n __x64_sys_unlinkat+0x63/0x90\n do_syscall_64+0x115/0x6a0\n entry_SYSCALL_64_after_hwframe+0x77/0x7f"
}
],
"id": "CVE-2026-68367",
"lastModified": "2026-08-17T06:17:44.970",
"metrics": {},
"published": "2026-08-10T13:20:29.353",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/3118bb872c7dff653294f193d5328a476619e04d"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/4c6c6a5588b9a2f8437fb794e852d05fa60ebe53"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/79e2d75725c85607f8a9d87ae9cace62a19f767d"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/a6eb5a0ae7cd313cfd7df78decd8f43b64c68703"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/f282242906c12fd476b86757afba51f211d4f959"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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